Pre-weakened cover for an airbag and method of making

ABSTRACT

A pre-weakened cover of an airbag module is provided including a layer having an outer show surface and an opposing inner surface. A plurality of first cuts is arranged at a first angle on the inner surface. A plurality of second cuts is arranged at a second angle on the inner surface. Each of the second cuts intersects two adjacent first cuts to form a generally V-shaped pattern.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional PatentApplication No. 61/713,667 filed Oct. 15, 2012, the entire contents ofwhich are incorporated herein by reference thereto.

BACKGROUND

The present invention relates generally to an instrument panel, driverairbag cover or other interior trim part(s) cover used in a vehicle orany other item having an inflatable cushion or airbag module, and moreparticularly to an interior trim cover having an integral hidden doorand the method of manufacture thereof.

Vehicles are now equipped with some type of inflatable cushions orairbag modules and other vehicle components have been modified toaccommodate the use of such systems. For example, most passenger sideairbag modules are disposed within and behind an instrument panel whichextends across at least a portion of the width of a vehicle compartment.During assembly and/or manufacture, an instrument panel in a vehiclehaving a passenger side airbag module requires a discrete door whichcovers an opening formed in the instrument panel for the inflatablecushion to deploy through upon actuation of the airbag module. Thisseparate door is designed to open in response to the force of theexpanding inflatable cushion. In other words as the pressure in theinflatable cushion increases, the volume of the cushion increases andapplies a force to a portion of the door wherein the door selectivelyseparates from the remaining portion of the instrument panel to permitthe inflatable cushion to deploy therethrough.

Accordingly, it is desirable to provide a cover with a pre-weakened areaon one side that is not visually perceivable from an opposite side.

SUMMARY OF THE INVENTION

According to one exemplary embodiment of the present invention, apre-weakened cover of an airbag module is provided including a layerhaving an outer show surface and an opposing inner surface. A pluralityof first cuts and a plurality of second cuts are arranged on the innersurface. Each of the second cuts intersects two adjacent first cuts toform a generally V-shaped pattern.

In another exemplary embodiment, the layer with the outer show surfaceis a leather layer or a layer of simulated leather.

According to another embodiment of the invention, a method of making apre-weakened cover for an airbag module is provided including providinga layer having an outer show surface and an opposing inner surface. Aplurality of first cuts is formed in the inner surface at a first angle.A plurality of second cuts is formed in the inner surface at a secondangle. The plurality of first cuts and the plurality of second cuts forma generally V-shaped pattern.

In yet another embodiment, the method includes the step of pre-weakeninga leather layer or a layer of simulated leather that comprises the outershow surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example only,with reference to the accompanying drawings in which:

FIG. 1 is a partial perspective view of a vehicle interior;

FIG. 2 is a partial cross-sectional view of a vehicle interior;

FIG. 3 is a view of the outer layer along lines 3-3 of FIG. 1;

FIG. 3A is a view of a multiple layer instrument panel along the lines3-3 of FIG. 1; and

FIG. 4 is a top view of a tear seam according to an embodiment of thepresent invention; and

FIG. 5 is a top view of an alternate tear seam according to anembodiment of the present invention.

The above-described and other features and advantages of the presentapplication will be appreciated and understood by those skilled in theart from the following detailed description, drawings, and appendedclaims.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In accordance with exemplary embodiments of the present invention anairbag module cover/instrument panel with a deployable door andinvisible tear seam is provided. In one embodiment, a cutting device isused to provide the tear seam wherein, the tear seam formed by the scoreis not visually viewable from the outer or show surface of thecover/instrument panel. Non limiting examples of a cutting deviceinclude any type of device that can be effectively controlled to providethe desired depths in the scores whether uniform or varying.

In one non-limiting embodiment an ultrasonic embossing or scoring devicemay be used to score surface 44 wherein at least one blade is oscillatedat an ultrasonic frequency as it is advanced into the inner surface ofthe instrument panel cover to make a very precise cut or score. Thedepth of this score is controlled very precisely such that the at leastone blade will move within a given distance of the outer surface of theinstrument panel cover. In addition, the blade configuration itself maybe varied to provide the desired effect.

In one application and depending on the material used for the outerlayer, the oscillating blade effectively heats and melts the instrumentpanel cover material at the inner surface to form a given score.

Alternatively a knife or blade may be applied to the surface 44 via anoperating device that can effectively control and/or vary the depth ofthe cut or score in surface 44. In another embodiment and if applicable,a laser scoring device may be utilized.

By precisely controlling the depth of the score(s), the thickness of theremaining unscored material may be controlled and this is importantbecause it the remaining unscored material thickness which determinesthe force required for the deployment region to separate along thescore(s) to permit the air bag cushion to properly deploy therethrough.When the air bag cushion begins to inflate and build pressure therein,the force of the air bag cushion against the inner surface causes thescore(s) defining the periphery of the deployment region to tear orseparate to form an opening for the air bag cushion to passtherethrough.

The cover/instrument panel will provide a means for covering a portionof an airbag module, having an inflatable cushion that is positioned todeploy through the deployable door defined by the tear seams/seam of thecover/instrument panel. The pressure of the inflating cushion will causethe deployable door to pivot open while tearing along the tear seamspositioned in a portion of cover in order to provide an opening for theinflatable cushion to deploy therethrough while a portion of thedeployable door is still pivotally secured to the cover instrumentpanel.

Referring now to FIGS. 1-2, an instrument panel is generally indicatedat 10. The instrument panel 10 is assembled into a vehicle passengercompartment 12. The instrument panel 10 is generally disposed beneath awindshield 14 and extends across substantially the entire width of thepassenger compartment 12. The instrument panel 10 may additionallyinclude a deployment door 24 formed therein. The deployment door 24 isintended to be in the general area corresponding to a passenger sideairbag module 26 (see FIG. 2). Accordingly, the passenger side airbagmodule 26 is located and deployed therethrough during actuation underpredetermined deployment conditions.

An airbag module 26, such as the passenger side airbag module forexample, includes a housing 28, an inflator 30 and an inflatable cushion32. The inflator 30 inflates the inflatable cushion 32 in response to asignal 34 received from a sensing or control module 36 configured todetermine if an activation event is occurring. As is known in therelated arts, the control module 36 receives signals 34 from a pluralityof sensors disposed throughout the vehicle.

It is, of course, understood that the passenger side airbag module 26and the configuration of the instrument panel 10 illustrated in FIGS. 1and 2 are provided as examples and various other configurations of theinstrument panel 10 and the airbag module 26 are contemplated. Thus,various embodiments of the present invention are not intended to belimited to the specific configurations illustrated.

The instrument panel 10 may be formed from a plurality of layers, suchas an outer layer, an intermediary layer, and a substrate layer forexample, each comprising any of a number of suitable materials orcombinations thereof. Preferred materials are those materials that havethe desired characteristics of strength, durability, flexibility, andfinished appearance and feel for use as an instrument panel 10 or acover for a driver's side airbag module.

As shown in FIG. 3, an outer layer 18 includes an inner surface 44 thatmay be positioned adjacent an intermediary layer and an outer showsurface 20 that is exposed to the passenger compartment 12, andtherefore, to the occupants of the vehicle. Thus, the outer layer 18should be formed from a material that has an aesthetically pleasingouter appearance. In one embodiment, the outer layer 18 may be formedfrom a leather material, such as real leather or simulated leather forexample. The outer layer 18 acts as a cover for a portion of an airbagmodule 26, such as the airbag module 26 housed within the instrumentpanel 10 for example. The instrument panel 10 and cover of the airbagmodule 26 are formed with a tear seam 40 to facilitate the deployment ofan airbag module 26. For example, the tear seam 40 in the cover andinstrument panel 10 defines the deployment door 24 through which anairbag module 26 deploys.

FIG. 3A illustrates a cross-sectional view of a tear seam of aninstrument panel 10 in accordance with one non-limiting embodiment. Hereand as mentioned above the outer layer 18 has show surface 20 and aninner surface 44 and in this embodiment, the instrument panel/cover hasan intermediary foam layer 43 and a substrate layer 45. The combinationof the outer layer 18, foam layer 43 and substrate layer 45 whenseparated from the remaining portions of the instrument panel along thetear seam 40 define a deployment door opening in the cover/instrumentpanel. Of course, the deployment door may simply comprise outer layer 18and a foam layer 43. Alternatively, the cover or door may simplycomprise only outer layer 18. Still further the cover and/or door maycomprise layer 18 and any other combination of backing layers.

FIG. 3A shows one non-limiting embodiment wherein the deployment door oropening may be defined by a cut, groove or opening 41 or plurality ofcuts, grooves or openings 41 that extends into the cover/instrumentpanel from the substrate layer 45, into the foam layer 43 and then arealigned or partially aligned with the tear seam 40 formed in the innersurface 44 of the outer layer 18. However and as illustrated, the tearseam does not extend all the way through to the outer surface 20 ofouter layer 18. Thus, and when the cover or layer is installed in thevehicle the tear seam is not visible through the show surface.Alternatively, the tear seam 40 may only be formed in outer layer 18. Inyet another embodiment, the tear seam 40 formed in outer layer 18 may bealigned with a tear seam in the foam layer 43 and/or the substrate layer45. In yet another embodiment, the tear seam 40 formed in outer layer 18may be aligned with a tear seam in the foam layer 43 and/or thesubstrate layer 45. In still another embodiment, the tear seam 40 formedin outer layer 18 may be completely offset or partially offset from thetear seam in the foam layer 43 and/or the substrate layer 45 or may bepartially aligned or partially offset from the tear seam in the foamlayer 43 and/or the substrate layer 45 so that only a portion of thetear seam 40 is aligned with the tear seam openings in layers 43 and/or45.

Referring now to FIGS. 4 and 5, the tear seam 40 or a portion of thetear seam 40 includes a plurality of weakened regions 50 on the innersurface 44 of the outer layer 18 such that when the airbag module 26 isactuated, the outer layer 18 tears along this run of weakened regions50. In one embodiment, the weakened regions 50 of the tear seam 40 arearranged such that when the airbag module 26 is actuated, the deploymentdoor 24 separates from the remainder of the instrument panel 10 in aseries of generally V-shaped or zig-zag pattern. In one embodiment, thetear seam 40 includes a plurality of first cuts 52 and a plurality ofsecond cuts 58 formed at intervals along the periphery of the deployabledoor 24. The first and second cuts 52, 58 may be generally linear oralternatively may be generally curved. The first and second cuts 52, 58are non-uniform and consecutive cuts 52, 58 may vary in both shape andsize.

Each of the first cuts 52 are arranged at an angle 53 relative to thedeployable door 24. In one embodiment, the first cuts are arranged at asimilar angle, such as a 30 degree or 45 degree angle for example.Alternatively, the first cuts may be arranged at varying angles. Thesecond cuts 58 are also at an angle 59 to the deployable door 24 and areconfigured to intersect two adjacent first cuts 52 to form a series ofgenerally V-shaped cuts in the inner surface 44. The plurality of secondcuts 58 may be arranged at a similar angle. In one embodiment, theangles formed by the second cuts 58 are equal and opposite to the anglesformed by the first cuts 52. Alternatively, each of the second cuts 58may be arranged at a varying angle, and the angles of the second cuts 58may be distinct from the angles of by the first cuts 52.

The second cuts 58 intersect a first cut 52 near a first end 54 andintersect an adjacent first cut 52 near a second, opposite end 56. Theends of both the first cut 52 and the second cut 58 extend beyond theseintersections to weaken the portion of the outer layer 18 near theintersection. Consequently, the weakened regions 50 of the tear seam 40are therefore located at these intersections between the first cuts 52and the second cuts 58. By forming the first cuts and the second cuts asa mixture of both curved and linear cuts arranged (see at least FIG. 5)at different angles, the tear seam 40 created in the outer layer 18 willbe difficult to detect from the show surface 20 even as the outer layerages.

In one embodiment, a cutting or scoring device may be used to create thetear seam 40 and weakened regions 50 in the outer layer 18. Exemplarycutting and scoring devices include but are not limited to a knife,scalpel, rotary knife, and ultra-sonic knife for example. Alternatively,a needle punch may be used to generate the intersecting first and secondcuts 52, 58 of the tear seam 40. The cutting depth may vary betweenadjacent cuts 52, 58 and also may vary between the first end and thesecond end of each cut. In one embodiment, the cutting depth of theplurality of first cuts 52 and the plurality of second cuts 58 is deeperadjacent an intersection with an adjacent cut.

Though the outer layer 18 is described in the previous embodiment as acover for a passenger side airbag module 26 in an instrument panel 10,the outer layer 18 may also be used as a cover for other airbag modules26 in various locations throughout a vehicle. In particular, the outerlayer 18 may be incorporated into any surface (e.g., leather orotherwise) of the vehicle as a cover for an airbag module 26. Forinstance, the outer layer 18 may be integrated into a steering wheel,any of the seats in the vehicle, or the paneling on the side of a door.Moreover, the outer layer 18 may be used as a single layer or may beused in combination with other layers such as the intermediary layer andthe substrate layer or any combination thereof including other layers oronly just the outer layer 18 formed from leather or a simulated leathermaterial.

In accordance with various embodiments of the present invention, theinstrument panel may be formed from a plurality of layers eachcomprising any one of a number of suitable materials or combinationsthereof. In one embodiment, the instrument panel may be formed fromthermoplastic and thermoset materials and/or a leather material and/or asimulated leather material.

For example, suitable thermoplastic materials include but are notlimited to polyethylene based polyolefin elastomer or polypropylenebased thermoplastic elastomer, poly-urethane resins and otherco-polymers and equivalents thereof. Non-limiting examples include;thermoplastic elastic olefin (TEO), thermoplastic elastomer (TPE),thermoplastic elastomer-oefinic (TPE-O, TPO), thermoplasticelastomer-styrenic (TPE-S), Polycarbonate (PC),Polycarbonate/Acrylonitrile-Butadiene-Styrene (PC/ABS),Acrylonitrile-Butadiene-Styrene (ABS) copolymers, Poly-urethane (TPU)and Polyvinyl-Chloride (PVC).

Non-limiting examples of thermosets include but are not limited topolyamide, polybutadiene, polyether block amide (PEBA), polyetherimide,polyimide, polyurea, polyurethane (PUR), silicone, vinyl ester,phenolic, melamine, urea formaldehyde resins, Fluropolymers such aspolytetrafluorethylene (PTFE) and polyvinylidene fluoride (PVDF).

In one non-limiting embodiment the sheet, outer material or outer layer18 may be formed from materials including but not limited topolyurethane, poly vinyl chloride (PVC), imitation leather, real leatherproducts and any other equivalent material capable of providing thedesired show surface. After the sheet of material or outer layer 18 isformed the comprising the tear seam 40 are made in the outer layer 18.In one embodiment, the show surface 20 of the outer layer 18 may beconfigured to have a textured or grainy textured to provide anaesthetically pleasing appearance (e.g., a simulated leather texture).

It is, of course, understood that the passenger side airbag module andthe configuration of the instrument panel illustrated in the FIGS. areprovided as examples and various other configurations of the instrumentpanel and the airbag module are contemplated thus, the present inventionis not intended to be limited to the specific configurations illustratedin the FIGS.

Although a vehicle passenger side airbag is illustrated it is, ofcourse, understood that a deployable airbag door with an invisible tearseam may be formed over any type of vehicle airbag (e.g., driver side,seat, door module, side curtain airbag, knee bolster, etc.) inaccordance with various embodiments of the present invention.

Reference is made to the following U.S. Patents the contents each ofwhich are incorporated herein by reference thereto U.S. Pat. Nos.6,533,314; 6,689,306; 6,692,019; 6,921,105; and 7,093,850. Reference isalso made to the following U.S. Patent Publication U.S. 2008/0315566,the contents of which is also incorporated herein by reference thereto.

While the invention has been described with reference to an exemplaryembodiment, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment disclosed as the best modecontemplated for carrying out this invention, but that the inventionwill include all embodiments falling within the scope of the presentapplication.

What is claimed is:
 1. A pre-weakened cover of an airbag module,comprising: a leather layer member having an outer show surface and anopposing inner surface; a plurality of first cuts arranged on the innersurface; and a plurality of second cuts arranged on the inner surface,wherein each of the plurality of second cuts intersects two adjacentfirst cuts to form a generally V-shaped pattern wherein the plurality offirst cuts and the plurality of second cuts are formed by a knife,wherein a plurality of weakened regions are formed at the intersectionsbetween the plurality of first cuts and the plurality of second cuts andwherein each of the plurality of first cuts and the plurality of secondcuts each have end portions that extend past each intersection to weakenthe leather layer member near each intersection.
 2. The pre-weakenedcover according to claim 1, wherein each of the plurality of first cutsis arranged at a first angle.
 3. The pre-weakened cover according toclaim 2, wherein the first angle of each of the plurality of first cutsvaries.
 4. The pre-weakened cover according to claim 1, wherein each ofthe plurality of second cuts is arranged at a second angle.
 5. Thepre-weakened cover according to claim 4, wherein the second angle ofeach of the plurality of second cuts varies.
 6. The pre-weakened coveraccording to claim 1, wherein the plurality of first cuts and theplurality of second cuts are non-uniform in shape and size.
 7. Thepre-weakened cover according to claim 1, wherein the cover is configuredto tear along the generally V-shaped pattern between the plurality ofweakened regions.
 8. The pre-weakened cover according to claim 1,wherein the plurality of first cuts and the plurality of second cuts areonly formed in the leather layer member.
 9. A method of making apre-weakened cover of an airbag module comprising: providing a leatherlayer member having an outer show surface and an opposing inner surface;forming a plurality of first cuts in the inner surface at a first anglewith a knife; and forming a plurality of second cuts in the innersurface at a second angle with the knife such that the plurality offirst cuts and the plurality of second cuts form a generally V-shapedpattern, wherein a weakened region is formed at each intersectionbetween a second cut and a first cut and wherein each of the pluralityof first cuts and the plurality of second cuts each have end portionsthat extend past each intersection to weaken the leather layer membernear each intersection.
 10. The method according to claim 9, wherein thefirst angle of each of the plurality of first cuts varies.
 11. Themethod according to claim 9, wherein the second angle of each of theplurality of second cuts varies.
 12. The method according to claim 9,wherein the plurality of first cuts and the plurality of second cuts arenon-uniform in shape and size.
 13. The method according to claim 9,wherein the plurality of second cuts intersect two adjacent first cuts.14. The method according to claim 9, wherein the cover is configured totear along the generally V-shaped pattern between the plurality ofweakened regions.
 15. The method according to claim 9, wherein theplurality of first cuts and the plurality of second cuts are only formedin the leather layer member.